What is niacin used for?

Niacin may help to improve your blood fat levels by:

This may translate to a decrease in heart disease risk, although several studies have found no link between niacin supplementation and a decrease in heart disease risk or deaths (4, 5).

It also takes high doses of niacin, typically 1,500 mg or greater, to achieve blood fat level improvements, which increases the risk of experiencing unpleasant or potentially harmful side effects (6).

For these reasons, niacin is not a primary treatment for high cholesterol. It’s primarily used to help improve blood fat levels in people who cannot tolerate statin drugs (5, 7).

One role of niacin is to release prostaglandins, or chemicals that help your blood vessels widen — improving blood flow and reducing blood pressure. For this reason, niacin may play a role in the prevention or treatment of high blood pressure (8).

In one observational study of over 12,000 adults, researchers found that each 1 mg increase in daily niacin intake was associated with a 2% decrease in high blood pressure risk — with the lowest overall high blood pressure risk seen at a daily niacin intake of 14.3 to 16.7 mg per day (8).

A high quality study also noted that single doses of 100 mg and 500 mg of niacin slightly reduced right ventricular systolic pressure (9).

However, more research is needed to confirm these effects.

Type 1 diabetes is an autoimmune disease in which your body attacks and destroys insulin-creating cells in your pancreas.

There’s research to suggest that niacin could help protect those cells and possibly even lower the risk of type 1 diabetes in children who have a higher chance of developing this condition (10).

However, for people with type 2 diabetes, the role of niacin is more complicated.

On one hand, it can help lower the high cholesterol levels that are often seen in people with type 2 diabetes. On the other, it has the potential to increase blood sugar levels. As a result, people with diabetes who take niacin to treat high cholesterol also need to monitor their blood sugar carefully (11).

Fortunately, a more recent review of studies found that niacin did not have significant negative effects on blood sugar management in people with type 2 diabetes (12).

Your brain needs niacin — as a part of the coenzymes NAD and NADP — to get energy and function properly.

In fact, brain fog and even psychiatric symptoms are associated with niacin deficiency (1, 13).

Some types of schizophrenia can be treated with niacin, as it helps undo damage to brain cells that’s caused by a niacin deficiency (14).

Preliminary research shows that it could also help keep the brain healthy in cases of Alzheimer’s disease. However, results are mixed (15, 16).

Niacin helps protect skin cells from sun damage, whether it’s used orally or applied as a lotion (17).

• increasing your HDL (good) cholesterol.
• reducing your LDL (bad) LDL cholesterol.
• reducing your triglyceride levels.

Niacin may help to improve your blood fat levels by:

This may translate to a decrease in heart disease risk, although several studies have found no link between niacin supplementation and a decrease in heart disease risk or deaths (4, 5).

It also takes high doses of niacin, typically 1,500 mg or greater, to achieve blood fat level improvements, which increases the risk of experiencing unpleasant or potentially harmful side effects (6).

For these reasons, niacin is not a primary treatment for high cholesterol. It’s primarily used to help improve blood fat levels in people who cannot tolerate statin drugs (5, 7).

One role of niacin is to release prostaglandins, or chemicals that help your blood vessels widen — improving blood flow and reducing blood pressure. For this reason, niacin may play a role in the prevention or treatment of high blood pressure (8).

In one observational study of over 12,000 adults, researchers found that each 1 mg increase in daily niacin intake was associated with a 2% decrease in high blood pressure risk — with the lowest overall high blood pressure risk seen at a daily niacin intake of 14.3 to 16.7 mg per day (8).

A high quality study also noted that single doses of 100 mg and 500 mg of niacin slightly reduced right ventricular systolic pressure (9).

However, more research is needed to confirm these effects.

Type 1 diabetes is an autoimmune disease in which your body attacks and destroys insulin-creating cells in your pancreas.

There’s research to suggest that niacin could help protect those cells and possibly even lower the risk of type 1 diabetes in children who have a higher chance of developing this condition (10).

However, for people with type 2 diabetes, the role of niacin is more complicated.

On one hand, it can help lower the high cholesterol levels that are often seen in people with type 2 diabetes. On the other, it has the potential to increase blood sugar levels. As a result, people with diabetes who take niacin to treat high cholesterol also need to monitor their blood sugar carefully (11).

Fortunately, a more recent review of studies found that niacin did not have significant negative effects on blood sugar management in people with type 2 diabetes (12).

Your brain needs niacin — as a part of the coenzymes NAD and NADP — to get energy and function properly.

In fact, brain fog and even psychiatric symptoms are associated with niacin deficiency (1, 13).

Some types of schizophrenia can be treated with niacin, as it helps undo damage to brain cells that’s caused by a niacin deficiency (14).

Preliminary research shows that it could also help keep the brain healthy in cases of Alzheimer’s disease. However, results are mixed (15, 16).

Niacin helps protect skin cells from sun damage, whether it’s used orally or applied as a lotion (17).

It may help prevent certain types of skin cancer as well. One high quality study in over 300 people at high risk of skin cancer found that taking 500 mg of nicotinamide twice daily reduced rates of nonmelanoma skin cancer compared to a control (18).

Niacin is used with diet changes (restriction of cholesterol and fat intake) to reduce the amount of cholesterol (a fat-like substance) and other fatty substances in your blood and to increase the amount of high density lipoprotein (HDL; ''good cholesterol'').

RDA:  Niacin is measured in milligrams (mg) of niacin equivalents (NE). One NE equals 1 milligram of niacin or 60 mg of tryptophan. The Recommended Dietary Allowance (RDA) for adults 19+ years is 16 mg NE for men, 14 mg NE for women, 18 mg NE for pregnant women, and 17 mg NE for lactating women.

UL:  The Tolerable Upper Intake Level is the maximum daily intake unlikely to cause harmful effects on health. The UL for niacin for all adults 19+ years is 35 milligrams.

A niacin deficiency is rare because it is found in many foods, both from animals and plants.

Niacin is available as a supplement in the form of nicotinic acid or nicotinamide. Sometimes the amounts in supplements are far beyond the RDA, causing unpleasant side effects of flushing. Niacin supplements are also available as a prescription medicine that is used to treat high cholesterol; this typically comes in an extended release form of nicotinic acid that allows slower, more gradual absorption so that it does not cause flushing. Because of the very high doses of nicotinic acid needed, up to 2,000 mg daily, this supplement should only be used when monitored by a physician.

A niacin deficiency is rare in the United States and other industrialized countries because it is well-absorbed from most foods (with the exception of some cereal grains in which niacin is bound to its fibers, decreasing the absorption) and is added to many foods and multivitamins. A severe niacin deficiency leads to pellagra, a condition that causes a dark, sometimes scaly rash to develop on skin areas exposed to sunlight; bright redness of the tongue; and constipation/diarrhea. Other signs of severe niacin deficiency include:

Groups at risk for deficiency

Toxicity when eating foods containing niacin is rare, but can occur from long-term use of high-dose supplements. A reddened skin flush with itchiness or tingling on the face, arms, and chest is a common sign. Flushing occurs mainly when taking high-dosage supplements in the form of nicotinic acid, rather than nicotinamide. Niacin taken in large doses as supplements may also increase uric acid levels, which is a risk factor for gout.

Other signs:

B Vitamins Vitamins and Minerals

Last reviewed March 2023

Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider. Side effects may include diarrhea, headache, stomach discomfort, and bloating.

High doses (50 mg or more) of niacin can cause side effects. The most common side effect is called "niacin flush," which is a burning, tingling sensation in the face and chest, and red or flushed skin. Taking an aspirin 30 minutes prior to the niacin may help reduce this symptom.

At very high doses, used to lower cholesterol and treat other conditions, liver damage and stomach ulcers can occur. Your doctor will regularly check your liver function through a blood test.

People with a history of liver disease, kidney disease, or stomach ulcers should not take niacin supplements. Those with diabetes or gallbladder disease should do so only under the close supervision of their doctors.

Stop taking niacin or niacinamide at least 2 weeks before a scheduled surgery.

Niacin and niacinamide may make allergies worse by increasing histamine.

People with low blood pressure should not take niacin or niacinamide because they may cause a dangerous drop in blood pressure. DO NOT take niacin if you have a history of gout.

People with coronary artery disease or unstable angina should not take niacin without their doctor's supervision, as large doses can raise the risk of heart rhythm problems.